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Khalilpour J, Soltani Zangbar H, Alipour MR, Shahabi P. The hypoxic respiratory response of the pre-Bötzinger complex. Heliyon 2024; 10:e34491. [PMID: 39114066 PMCID: PMC11305331 DOI: 10.1016/j.heliyon.2024.e34491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/18/2024] [Accepted: 07/10/2024] [Indexed: 08/10/2024] Open
Abstract
Since the discovery of the pre-Bötzinger Complex (preBötC) as a crucial region for generating the main respiratory rhythm, our understanding of its cellular and molecular aspects has rapidly increased within the last few decades. It is now apparent that preBötC is a highly flexible neuronal network that reconfigures state-dependently to produce the most appropriate respiratory output in response to various metabolic challenges, such as hypoxia. However, the responses of the preBötC to hypoxic conditions can be varied based on the intensity, pattern, and duration of the hypoxic challenge. This review discusses the preBötC response to hypoxic challenges at the cellular and network level. Particularly, the involvement of preBötC in the classical biphasic response of the respiratory network to acute hypoxia is illuminated. Furthermore, the article discusses the functional and structural changes of preBötC neurons following intermittent and sustained hypoxic challenges. Accumulating evidence shows that the preBötC neural circuits undergo substantial changes following hypoxia and contribute to several types of the respiratory system's hypoxic ventilatory responses.
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Affiliation(s)
- Jamal Khalilpour
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hamid Soltani Zangbar
- Department of Neuroscience, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Parviz Shahabi
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
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Liu Y, Tan J, Miao Y, Zhang Q. Neurogenesis, A Potential Target for Intermittent Hypoxia Leading to Cognitive Decline. Curr Stem Cell Res Ther 2024; 19:63-70. [PMID: 37005547 DOI: 10.2174/1574888x18666230330083206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 01/30/2023] [Accepted: 02/06/2023] [Indexed: 04/04/2023]
Abstract
As a sleep breathing disorder, characterized by intermittent hypoxia (IH) and Obstructive sleep apnea (OSA), is believed to decrease the cognitive function of patients. Many factors are thought to be responsible for cognitive decline in OSA patients. Neurogenesis, a process by which neural stem cells (NSCs) differentiate into new neurons in the brain, is a major determinant affecting cognitive function. However, there is no clear relationship between IH or OSA and neurogenesis. In recent years, increasing numbers of studies on IH and neurogenesis are documented. Therefore, this review summarizes the effects of IH on neurogenesis; then discusses the influencing factors that may cause these effects and the potential signaling pathways that may exist. Finally, based on this impact, we discuss potential methods and future directions for improving cognition.
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Affiliation(s)
- Yuxing Liu
- Department of Geriatrics, Tianjin Medical University General Hospital, Tianjin Geriatrics Institute, Tianjin, China
| | - Jin Tan
- Department of Geriatrics, Tianjin Medical University General Hospital, Tianjin Geriatrics Institute, Tianjin, China
| | - Yuyang Miao
- Department of Geriatrics, Tianjin Medical University General Hospital, Tianjin Geriatrics Institute, Tianjin, China
| | - Qiang Zhang
- Department of Geriatrics, Tianjin Medical University General Hospital, Tianjin Geriatrics Institute, Tianjin, China
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Kang J, Lu N, Yang S, Guo B, Zhu Y, Wu S, Huang X, Wong-Riley MTT, Liu YY. Alterations in synapses and mitochondria induced by acute or chronic intermittent hypoxia in the pre-Bötzinger complex of rats: an ultrastructural triple-labeling study with immunocytochemistry and histochemistry. Front Cell Neurosci 2023; 17:1132241. [PMID: 37396926 PMCID: PMC10312010 DOI: 10.3389/fncel.2023.1132241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 06/05/2023] [Indexed: 07/04/2023] Open
Abstract
Introduction The pre-Bötzinger complex (pre-BötC), a kernel of inspiratory rhythmogenesis, is a heterogeneous network with excitatory glutamatergic and inhibitory GABAergic and glycinergic neurons. Inspiratory rhythm generation relies on synchronous activation of glutamatergic neuron, whilst inhibitory neurons play a critical role in shaping the breathing pattern, endowing the rhythm with flexibility in adapting to environmental, metabolic, and behavioral needs. Here we report ultrastructural alterations in excitatory, asymmetric synapses (AS) and inhibitory, symmetric synapses (SS), especially perforated synapses with discontinuous postsynaptic densities (PSDs) in the pre-BötC in rats exposed to daily acute intermittent hypoxia (dAIH) or chronic (C) IH. Methods We utilized for the first time a combination of somatostatin (SST) and neurokinin 1 receptor (NK1R) double immunocytochemistry with cytochrome oxidase histochemistry, to reveal synaptic characteristics and mitochondrial dynamic in the pre-BötC. Results We found perforated synapses with synaptic vesicles accumulated in distinct pools in apposition to each discrete PSD segments. dAIH induced significant increases in the PSD size of macular AS, and the proportion of perforated synapses. AS were predominant in the dAIH group, whereas SS were in a high proportion in the CIH group. dAIH significantly increased SST and NK1R expressions, whereas CIH led to a decrease. Desmosome-like contacts (DLC) were characterized for the first time in the pre-BötC. They were distributed alongside of synapses, especially SS. Mitochondria appeared in more proximity to DLC than synapses, suggestive of a higher energy demand of the DLC. Findings of single spines with dual AS and SS innervation provide morphological evidence of excitation-inhibition interplay within a single spine in the pre-BötC. In particular, we characterized spine-shaft microdomains of concentrated synapses coupled with mitochondrial positioning that could serve as a structural basis for synchrony of spine-shaft communication. Mitochondria were found within spines and ultrastructural features of mitochondrial fusion and fission were depicted for the first time in the pre-BötC. Conclusion We provide ultrastructural evidence of excitation-inhibition synapses in shafts and spines, and DLC in association with synapses that coincide with mitochondrial dynamic in their contribution to respiratory plasticity in the pre-BötC.
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Affiliation(s)
- Junjun Kang
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
| | - Naining Lu
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
| | - Shoujing Yang
- Department of Pathology, The Fourth Military Medical University, Xi’an, China
| | - Baolin Guo
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
| | - Yuanyuan Zhu
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
| | - Shengxi Wu
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
| | - Xiaofeng Huang
- Department of Pathology, Xi’an Gaoxin Hospital, Xi’an, China
| | - Margaret T. T. Wong-Riley
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ying-Ying Liu
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
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Song C, Zhao J, Hao J, Mi D, Zhang J, Liu Y, Wu S, Gao F, Jiang W. Aminoprocalcitonin protects against hippocampal neuronal death via preserving oxidative phosphorylation in refractory status epilepticus. Cell Death Discov 2023; 9:144. [PMID: 37142587 PMCID: PMC10160063 DOI: 10.1038/s41420-023-01445-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 05/06/2023] Open
Abstract
Refractory status epilepticus (RSE) is a neurological emergency where sustaining seizure causes severe neuronal death. Currently, there is no available neuroprotectant effective in RSE. Aminoprocalcitonin (NPCT) is a conserved peptide cleaved from procalcitonin, but its distribution and function in the brain remain enigmatic. Survival of neurons relies on sufficient energy supply. Recently, we found that NPCT was extensively distributed in the brain and had potent modulations on neuronal oxidative phosphorylation (OXPHOS), suggesting that NPCT might be involved in neuronal death by regulating energy status. In the present study, combining biochemical and histological methods, high-throughput RNA-sequence, Seahorse XFe analyser, an array of mitochondria function assays, and behavior-electroencephalogram (EEG) monitoring, we investigated the roles and translational values of NPCT in neuronal death after RSE. We found that NPCT was extensively distributed throughout gray matters in rat brain while RSE triggered NPCT overexpression in hippocampal CA3 pyramidal neurons. High-throughput RNA-sequence demonstrated that the influences of NPCT on primary hippocampal neurons were enriched in OXPHOS. Further function assays verified that NPCT facilitated ATP production, enhanced the activities of mitochondrial respiratory chain complexes I, IV, V, and increased neuronal maximal respiration capacity. NPCT exerted multiple neurotrophic effects including facilitating synaptogenesis, neuritogenesis, spinogenesis, and suppression of caspase-3. A polyclonal NPCT immunoneutralization antibody was developed to antagonize NPCT. In the in vitro 0-Mg2+ seizure model, immunoneutralization of NPCT caused more neuronal death, while exogenous NPCT supplementation, though did not reverse death outcomes, preserved mitochondrial membrane potential. In rat RSE model, both peripheral and intracerebroventricular immunoneutralization of NPCT exacerbated hippocampal neuronal death and peripheral immunoneutralization increased mortality. Intracerebroventricular immunoneutralization of NPCT further led to more serious hippocampal ATP depletion, and significant EEG power exhaustion. We conclude that NPCT is a neuropeptide regulating neuronal OXPHOS. During RSE, NPCT was overexpressed to protect hippocampal neuronal survival via facilitating energy supply.
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Affiliation(s)
- Changgeng Song
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Jingjing Zhao
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Jianmin Hao
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Dan Mi
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Jiajia Zhang
- National Translational Science Centre for Molecular Medicine & Department of Cell Biology, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Yingying Liu
- Department of Neurobiology, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Shengxi Wu
- Department of Neurobiology, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China
| | - Fang Gao
- Department of Neurobiology, Institute of Neurosciences, School of Basic Medicine, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China.
| | - Wen Jiang
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, 169 Chang Le Xi Road, Xi'an, 710032, Shaanxi, China.
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Song Q, Huang W, Ye W, Yan H, Wang L, Yang Y, Cheng X, Zhang W, Zheng J, He P, He Y, Fang D, Han X. Neuroprotective Effects of Estrogen Through BDNF-Transient Receptor Potential Channels 6 Signaling Pathway in the Hippocampus in a Rat Model of Perimenopausal Depression. Front Aging Neurosci 2022; 14:869274. [PMID: 35875795 PMCID: PMC9305198 DOI: 10.3389/fnagi.2022.869274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 06/07/2022] [Indexed: 12/18/2022] Open
Abstract
Estradiol (E2) has been proven to be effective in treating perimenopausal depression (PD); however, the downstream signaling pathways have not been fully elucidated. Transient receptor potential channels 6 (TRPC6) plays a vital role in promoting neuronal development and the formation of excitatory synapses. At present, we found that the serum levels of E2 and brain-derived neurotrophic factor (BDNF) declined significantly in the women with PD compared to perimenopausal women, which was accompanied by a clear reduction in TRPC6 levels. To further reveal the effects of TRPC6 on neuronal survival and excitability, the PD-like rat model was established by the total removal of left ovary and 80% removal of right ovary followed by 21 days of the chronic unpredictable mild stress. Intragastric administration of E2 (2 mg/kg), intraperitoneal injection of BDNF/TrB signaling pathway inhibitor (K252a, 100 μg/kg) and TRPC6 agonist (OAG, 0.6 mg/kg), and intracerebroventricular infusion of anti-BDNF antibody for blocking BDNF (0.5 μg/24 μl/rat) daily for 21 days were conducted. The levels of BDNF and TRPC6 in rat serum were lower in PD rats compared to the control rats; the depression-like behavior was induced, the neuronal death rate in the hippocampus increased, and the thickness of postsynaptic density (PSD) and the number of asymmetric synapses decreased significantly in the PD group. E2 treatment greatly upregulated the serum levels of BDNF and TRPC6, the neuronal excitability indicated by an elevation in the PSD thickness and the numbers of asymmetric synapses, and these actions were reversed by K252a; co-administration of TRPC6 agonist and K252a improved neuronal degeneration and increased the neuronal excitability induced in the E2-treated PD rats. K252a or anti-BDNF antibody inhibited the increased neuronal BDNF and TRPC6 expression in E2-treated PD rats; co-treatment of TRPC6 agonist and anti-BDNF antibody reduced neuronal death and increased the BDNF and TRPC6 expression in the hippocampal CA1 neurons in the E2-treated PD rats. These results suggest that the neuroprotective role of E2 in PD is closely related to enhance the activity of BDNF/TRPC6 pathway and is helpful to provide new prevention and strategies.
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Ren K, Liu H, Guo B, Li R, Mao H, Xue Q, Yao H, Wu S, Bai Z, Wang W. Quercetin relieves D-amphetamine-induced manic-like behaviour through activating TREK-1 potassium channels in mice. Br J Pharmacol 2021; 178:3682-3695. [PMID: 33908633 DOI: 10.1111/bph.15510] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Quercetin is a well-known plant flavonoid with neuroprotective properties. Earlier work suggested it may relieve psychiatric disorders, cognition deficits and memory dysfunction through anti-oxidant and/or radical scavenging mechanisms. In addition, quercetin modulated the physiological function of some ion channels. However, the detailed ionic mechanisms of the bioeffects of quercetin remain unknown. EXPERIMENTAL APPROACH Effects of quercetin on neuronal activities in the prefrontal cortex (PFC) and its ionic mechanisms were analysed by calcium imaging using mice bearing a green fluorescent protein, calmodulin, and M13 fusion protein and patch clamp in acute brain slices from C57BL/6 J mice and in HEK 293 cells. The possible ionic mechanism of action of quercetin on D-amphetamine-induced manic-like effects in mice was explored with c-fos staining and the open field behaviour test. KEY RESULTS Quercetin reduced calcium influx triggered by PFC pyramidal neuronal activity. This effect involved increasing the rheobase of neuronal firing through decreasing membrane resistance following quercetin treatment. Spadin, a blocker of TREK-1 potassium channels, also blocked the effect of quercetin on the membrane resistance and neuronal firing. Further, spadin blocked the neuroprotective effects of quercetin. The effects of quercetin on TREK-1 channels could be mimicked by GF109203X, a protein kinase C inhibitor. In vivo, injection of quercetin relieved the manic hyperlocomotion in mice, induced by D-amphetamine. This action was partly alleviated by spadin. CONCLUSION AND IMPLICATIONS TREK-1 channels are a novel target for quercetin, by inhibiting PKC. This action could contribute to both the neuroprotective and anti-manic-like effects.
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Affiliation(s)
- Keke Ren
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi'an, China.,College of Life Sciences and Research Center for Resource Peptide Drugs, Shaanxi Engineering and Technological Research Center for Conversation and Utilization of Regional Biological Resources, Yanan University, Yanan, China
| | - Haiying Liu
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Baolin Guo
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Rui Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Honghui Mao
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Qian Xue
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Han Yao
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Shengxi Wu
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
| | - Zhantao Bai
- College of Life Sciences and Research Center for Resource Peptide Drugs, Shaanxi Engineering and Technological Research Center for Conversation and Utilization of Regional Biological Resources, Yanan University, Yanan, China
| | - Wenting Wang
- Department of Neurobiology, School of Basic Medicine, Fourth Military Medical University, Xi'an, China
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Kanth K, Park K, Seyal M. Severity of Peri-ictal Respiratory Dysfunction With Epilepsy Duration and Patient Age at Epilepsy Onset. Front Neurol 2021; 11:618841. [PMID: 33391175 PMCID: PMC7775547 DOI: 10.3389/fneur.2020.618841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 12/01/2020] [Indexed: 11/13/2022] Open
Abstract
Respiratory dysfunction preceding death is fundamental in sudden unexpected death in epilepsy (SUDEP) pathophysiology. Hypoxia occurs with one-third of seizures. In temporal lobe epilepsy, there is volume loss in brainstem regions involved in autonomic control and increasing neuropathological changes with duration of epilepsy suggesting increasingly impaired regulation of ventilation. In animal models, recurrent hypoxic episodes induce long-term facilitation (LTF) of ventilatory function, however, LTF is less robust in older animals. LTF of ventilation may, to some degree, ameliorate the deleterious effects of progressive brainstem atrophy. We investigated the possibility that the duration of epilepsy, or age at epilepsy onset, may impact the severity of seizure-associated respiratory dysfunction. Patients with focal epilepsy undergoing video-EEG telemetry in the epilepsy monitoring unit (EMU) were studied. We found a significant relationship between age at epilepsy onset and duration of peri-ictal oxygen desaturation for focal seizures not progressing to bilateral tonic-clonic seizures, with longer duration of peri-ictal oxygen desaturation in patients with epilepsy onset at an older age but no significant relationships between duration of epilepsy or age at EMU admission and ventilatory dysfunction. Our findings suggest an intriguing possibility that LTF of ventilation may be protective when epilepsy starts at a younger age.
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Affiliation(s)
- Kiran Kanth
- Department of Neurology, University of California, Davis, Sacramento, CA, United States
| | - Katherine Park
- Department of Neurology, University of California, Davis, Sacramento, CA, United States
| | - Masud Seyal
- Department of Neurology, University of California, Davis, Sacramento, CA, United States
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Ma SB, Xian H, Wu WB, Ma SY, Liu YK, Liang YT, Guo H, Kang JJ, Liu YY, Zhang H, Wu SX, Luo C, Xie RG. CCL2 facilitates spinal synaptic transmission and pain via interaction with presynaptic CCR2 in spinal nociceptor terminals. Mol Brain 2020; 13:161. [PMID: 33228784 PMCID: PMC7685578 DOI: 10.1186/s13041-020-00701-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022] Open
Abstract
Previous studies have shown that CCL2 may cause chronic pain, but the exact mechanism of central sensitization is unclear. In this article, we further explore the presynaptic role of CCL2. Behavioral experiments show that intervertebral foramen injection CCR2 antagonists into dorsal root ganglion (DRG) can inhibit the inflammatory pain caused by CCL2 in spinal cord. We raised the question of the role of presynaptic CCR2 in the spinal dorsal horn. Subsequent electron microscopy experiments showed that CCR2 was expressed in the presynaptic CGRP terminal in the spinal dorsal horn. CCL2 can enhance presynaptic calcium signal. Whole-cell patch-clamp recordings showed that CCL2 can enhance NMDAR-eEPSCs through presynaptic effects, and further application of glutamate sensor method proved that CCL2 can act on presynaptic CCR2 to increase the release of presynaptic glutamate. In conclusion, we suggest that CCL2 can directly act on the CCR2 on presynaptic terminals of sensory neurons in the spinal dorsal horn, leading to an increase in the release of presynaptic glutamate and participate in the formation of central sensitization.
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Affiliation(s)
- Sui-Bin Ma
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China
| | - Hang Xian
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China.,Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Wen-Bin Wu
- The Fourth Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Shuo-Yao Ma
- The Sixth Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Ke Liu
- The Second Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Tong Liang
- The Second Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Huan Guo
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China.,Pain and Related Diseases Research Laboratory, Medical College of Shantou University, Shantou, 515041, China
| | - Jun-Jun Kang
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China
| | - Ying-Ying Liu
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China
| | - Hui Zhang
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China.,Department of Health Statistics, Fourth Military Medical University, Xi'an, 710032, China
| | - Sheng-Xi Wu
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China
| | - Ceng Luo
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China.
| | - Rou-Gang Xie
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China.
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Kang JJ, Fung ML, Zhang K, Lam CS, Wu SX, Huang XF, Yang SJ, Wong-Riley MTT, Liu YY. Chronic intermittent hypoxia alters the dendritic mitochondrial structure and activity in the pre-Bötzinger complex of rats. FASEB J 2020; 34:14588-14601. [PMID: 32910512 DOI: 10.1096/fj.201902141r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 07/21/2020] [Accepted: 08/17/2020] [Indexed: 11/11/2022]
Abstract
Mitochondrial bioenergetics is dynamically coupled with neuronal activities, which are altered by hypoxia-induced respiratory neuroplasticity. Here we report structural features of postsynaptic mitochondria in the pre-Bötzinger complex (pre-BötC) of rats treated with chronic intermittent hypoxia (CIH) simulating a severe condition of obstructive sleep apnea. The subcellular changes in dendritic mitochondria and histochemistry of cytochrome c oxidase (CO) activity were examined in pre-BötC neurons localized by immunoreactivity of neurokinin 1 receptors. Assays of mitochondrial electron transport chain (ETC) complex I, IV, V activities, and membrane potential were performed in the ventrolateral medulla containing the pre-BötC region. We found significant decreases in the mean length and area of dendritic mitochondria in the pre-BötC of CIH rats, when compared to the normoxic control and hypoxic group with daily acute intermittent hypoxia (dAIH) that evokes robust synaptic plasticity. Notably, these morphological alterations were mainly observed in the mitochondria in close proximity to the synapses. In addition, the proportion of mitochondria presented with enlarged compartments and filamentous cytoskeletal elements in the CIH group was less than the control and dAIH groups. Intriguingly, these distinct characteristics of structural adaptability were observed in the mitochondria within spatially restricted dendritic spines. Furthermore, the proportion of moderately to darkly CO-reactive mitochondria was reduced in the CIH group, indicating reduced mitochondrial activity. Consistently, mitochondrial ETC enzyme activities and membrane potential were lowered in the CIH group. These findings suggest that hypoxia-induced respiratory plasticity was characterized by spatially confined mitochondrial alterations within postsynaptic spines in the pre-BötC neurons. In contrast to the robust plasticity evoked by dAIH preconditioning, a severe CIH challenge may weaken the local mitochondrial bioenergetics that the fuel postsynaptic activities of the respiratory motor drive.
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Affiliation(s)
- Jun-Jun Kang
- Department of Neurobiology, The Fourth Military Medical University, Xi'an, China
| | - Man-Lung Fung
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Kun Zhang
- Department of Neurobiology, The Fourth Military Medical University, Xi'an, China
| | - Chun-Sing Lam
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Sheng-Xi Wu
- Department of Neurobiology, The Fourth Military Medical University, Xi'an, China
| | - Xiao-Feng Huang
- Department of Pathology and Pathophysiology, The Fourth Military Medical University, Xi'an, China
| | - Shou-Jing Yang
- Department of Pathology and Pathophysiology, The Fourth Military Medical University, Xi'an, China
| | - Margaret T T Wong-Riley
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ying-Ying Liu
- Department of Neurobiology, The Fourth Military Medical University, Xi'an, China
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